1. Field of Invention
This invention pertains to a device useful in conjunction with teaching aids, and more particularly to a device useful as a teaching aid for demonstrating probability theory in conjunction with an illuminating device such as an overhead projector.
2. Background of the Invention
Overhead projectors constitute a particular type of teaching aid very useful for displaying various information to a large number of students. Typically the displayed information, including text, pictures, drawings, graphs and so on is first transposed to a transparent sheet. Alternatively the lecturer can draw various figures or make notes directly on a blank transparent sheet. The image from the sheet is then projected unto a screen by the projector. In some instances, a direct demonstration using actual objects or models rather than pictures or drawings is more effective.
A very effective teaching aid for teaching probability is a die or pair of dice. However because most dice, models or similar teaching aids are opaque and because the overhead projector displays a two dimensional image, demonstrations making use of actual dice, models or similar objects cannot be made using an overhead projector. Alternatively, if a transparent model is used, the indicia on one face will interfere with the indicia on the face directly opposite when placed on the projector.